The article of manufacture which is currently used most often in the marketplace for packaging, transporting and distributing liquid, in particular soft carbonated and non-carbonated beverages, is a typically clear bottle-like package. These packages are stacked in multi-tier arrangements in sufficiently robust pre-formed containers or in palletized loads wrapped by means of heat-shrinking plastic film.
Thanks to their widely known characteristics, these plastic bottles are particularly well suited for the abovementioned applications in a number of respects such as providing good storage conditions for the beverage, providing an immediate identification of the beverage in the bottle, providing excellent impact strength and being lightweight. These characteristics prove quite advantageous during transport and handling operations. Above all, however, these bottles are fully utilizable by consumers and do not impose the necessity of a recovery considering their absolutely modest cost.
This type of bottle also provides wide safety margins against mechanical damage and excellent transportability. However, the currently available bottles have a number of drawbacks that quite frequently lead to practical complications in their use and give rise to high costs in the manufacture thereof.
Plastic bottles can be grouped into two distinct categories, i.e. for carbonated beverages and non-carbonated beverages.
The bottles intended for containing non-carbonated beverages are filled without a gas under pressure, and can be provided with an outer surface defining one or more horizontal grooves of a height of up to several centimeters, which make it more convenient for the user to seize and hold the bottle.
While these grooves also contribute to the mechanical strength of the bottle when it is subject to a vertical load, i.e. a condition that arises when the bottles are full and stacked on each other in multi-tier arrangements, the grooves nonetheless present a serious drawback in that they do not allow the bottles to be filled with carbonated beverages or, at any rate, to be used with a liquid under pressure in excess of 2 or 3 bars. As a matter of fact, such an inner pressure would inevitably stretch the plastic forming the grooves and, ultimately, the bottles would elongate by as much as several millimeters.
When these bottles are then piled upon each other in multitier arrangements, this elongation adds up to an amount which is by no means acceptable considering the strict dimensional constraints imposed by the final bottles.
In order to avoid this drawback, plastic bottles with a plainly smooth or almost smooth surface are used to contain carbonated or, anyway, pressurized beverages.
However, although the problem of the elongation of the bottles due to the internal pressure is eliminated, this measure brings about a new problem. Due to the thin wall-thickness of the plastic bottle and its characteristic of great flexibility under bending load, a normal plastic bottle of the above-described type proves very inconvenient to handle owing to both the fact that it lacks any suitable grip, which prevents small-handed persons, e.g. children, from being able to seize and handle the bottle with a single hand, and to the fact that, even if the bottle has been properly seized with a single hand, the bottle is bent or deformed accidentally by a simple pressure of the hand while pouring the contents from the bottle. This usually causes the pouring opening of the bottle to bend sidewards and the liquid to be spilled. It is of course possible to increase the wall thickness of the bottle, but this would lead to a considerable increase in costs since such bottles are normally mass-produced in very large quantities, i.e. up to several thousands per hour for each plant.
Apart from these considerations, it is quite apparent that it still is most suitable to use two distinct, different types of bottles for pressurized and non-pressurized beverages. However, this obviously places an additional burden on the manufacturer in terms of both management and organization complexity and manufacturing-related complications.
Furthermore, both of the above-described types of bottles have two further drawbacks.
1) The bottoms of the bottles are formed by an extension of the side cylindrical wall which is divided into a plurality of regular, similar bulges that are arranged regularly in a circle and are oriented downwards.
The external contour of said bulges is inscribed in a geometric half-sphere that closes the bottle in its lower section and that has, as its great circle, the same lower section of the cylinder forming the bottle.
The petaloid formed by said bulges only extends to a certain extent downwards, i.e. down to a certain depth, so that it can form the bearing surface of the bottle. The partial hemisphere-like curvature of the petaloid is to allow the bulges to take on the slightest possible deformation due to the combined, but antagonistic effect of the superimposed load and the internal pressure.
However, the bearing surface of the bottle is in this way reduced to a considerable extent, with the consequence of the obvious, undesired effects on the stability of the bottle itself, particularly when uncapped, which may be brought about by even the slightest impact or push. In order to do away with that particular drawback, special plastic bases having a circular, cover-like shape have been developed, which, when attached externally to the bottom of the bottle, are instrumental in increasing the size of the bearing base of the bottle itself. However, it is quite apparent that this measure brings about the inevitable complication of an additional manufacturing operation and the addition of the related material and manufacturing costs.
2) The second drawback derives from the fact that paper labels, which usually are applied onto the outer surface of the bottle,rub against adjacent bottles or the walls of holding or guiding/conveying means during handling and are thus quite likely to become damaged or torn off. This gives rise to clear inconveniences for the consumer, to a certain loss of image of the contents of the bottles, as well as to the necessity of sorting out the damaged bottles when re-applying the missing or damaged labels.